Basic cursor movement, handling end of buffer, end of line in drawing

src/text_editor/buffer.cpp

@@ -252,17 +252,22 @@ Line FindLine(Buffer &buffer, int64_t pos) {
     return {};
 }
 
-int64_t AdjustUTF8Pos(const Buffer &buffer, int64_t pos, int64_t direction = 1) {
+int64_t AdjustUTF8Pos(String string, int64_t pos, int64_t direction) {
-    int64_t result = pos;
+    for (; pos >= 0 && pos < string.len;) {
-    for (; result >= 0 && result < buffer.len;) {
+        if (IsUTF8ContinuationByte(string.data[pos])) {
-        char c = GetChar(buffer, pos);
+            pos += direction;
-        if (IsUTF8ContinuationByte(c)) {
-            result += direction;
         } else {
             break;
         }
     }
-    return result;
+    return pos;
+}
+
+int64_t AdjustUTF8Pos(const Buffer &buffer, int64_t pos, int64_t direction = 1, bool clamp = true) {
+    String string = GetString(buffer);
+    pos           = AdjustUTF8Pos(string, pos, direction);
+    if (clamp) pos = Clamp(buffer, pos);
+    return pos;
 }
 
 uint32_t GetUTF32(Buffer &buffer, int64_t pos, int64_t *codepoint_size) {
@@ -317,7 +322,7 @@ void Advance(BufferIter *iter) {
     if (iter->direction == ITERATE_FORWARD) {
         iter->pos += iter->utf8_codepoint_size;
     } else {
-        iter->pos = AdjustUTF8Pos(*iter->buffer, iter->pos - 1, ITERATE_BACKWARD);
+        iter->pos = AdjustUTF8Pos(*iter->buffer, iter->pos - 1, ITERATE_BACKWARD, false);
     }
 
     if (!IsValid(*iter)) return;

src/text_editor/main.cpp

@@ -68,6 +68,18 @@ void DrawString(Font font, String text, Vector2 position, float fontSize, float
     }
 }
 
+int64_t MoveRight(Buffer &buffer, int64_t pos) {
+    int64_t result = pos + 1;
+    result         = AdjustUTF8Pos(buffer, result);
+    return result;
+}
+
+int64_t MoveLeft(Buffer &buffer, int64_t pos) {
+    int64_t result = pos - 1;
+    result         = AdjustUTF8Pos(buffer, result, -1);
+    return result;
+}
+
 int main() {
     InitScratch();
     RunBufferTests();
@@ -76,9 +88,10 @@ int main() {
     SetTargetFPS(60);
 
     InitArena(&FrameArena);
-    float font_size    = 25;
+    float font_size    = 64;
     float font_spacing = 1;
     Font  font         = LoadFontEx("C:/Windows/Fonts/times.ttf", (int)font_size, NULL, 250);
+    if (0) font = LoadFontEx("C:/Windows/Fonts/consola.ttf", (int)font_size, NULL, 250);
 
     Array<Window> windows = {};
     windows.add({GetScreenRectRenderUnits()});
@@ -86,11 +99,13 @@ int main() {
         Window *window = &windows[0];
         Buffer *buffer = &window->buffer;
         InitBuffer(buffer);
+        if (0) {
             for (int i = 0; i < 100; i += 1) {
                 Array<Edit> edits = {FrameArena};
                 AddEdit(&edits, GetEnd(*buffer), Format(FrameArena, "line number: %d\n", i));
                 ApplyEdits(buffer, edits);
             }
+        }
 
         window->cursors.add({});
     }
@@ -100,7 +115,7 @@ int main() {
         {
             Window *focused_window = &windows[0];
 
-            if (IsMouseButtonDown(MOUSE_BUTTON_LEFT) || IsKeyDown(KEY_SPACE)) {
+            if (IsKeyDown(KEY_F1)) {
                 camera_offset_world_to_render_units = Vector2Subtract(camera_offset_world_to_render_units, GetMouseDelta());
             }
 
@@ -116,14 +131,21 @@ int main() {
                 }
 
                 Array<Edit> edits = {FrameArena};
-                For(focused_window->cursors) {
+                For(focused_window->cursors) AddEdit(&edits, it, string);
-                    AddEdit(&edits, it, string);
-                }
                 ApplyEdits(&focused_window->buffer, edits);
+                For(focused_window->cursors)
+                    it.max = it.min = MoveRight(focused_window->buffer, it.min);
             }
 
-            if (IsKeyPressed(KEY_F1)) {
+            if (IsKeyPressed(KEY_LEFT) || IsKeyPressedRepeat(KEY_LEFT)) {
-                font = LoadFontEx("C:/Windows/Fonts/consola.ttf", (int)font_size, NULL, 250);
+                For(focused_window->cursors) {
+                    it.max = it.min = MoveLeft(focused_window->buffer, it.min);
+                }
+            }
+            if (IsKeyPressed(KEY_RIGHT) || IsKeyPressedRepeat(KEY_RIGHT)) {
+                For(focused_window->cursors) {
+                    it.max = it.min = MoveRight(focused_window->buffer, it.min);
+                }
             }
         }
 
@@ -131,7 +153,6 @@ int main() {
         ClearBackground(RAYWHITE);
 
         ForItem(window, windows) {
-            // Draw the frame
             Rect2 window_rect_in_render_units = {
                 WorldToRenderUnits(window.rect_in_world_units.min, camera_offset_world_to_render_units),
                 WorldToRenderUnits(window.rect_in_world_units.max, camera_offset_world_to_render_units),
@@ -170,30 +191,41 @@ int main() {
                 int64_t     line;
             };
 
+            // Compute visible rows and cells
             Array<CellRow> rows = {FrameArena};
             for (int64_t line = line_min_y; line < line_max_y; line += 1) {
                 if (line < 0) break;
                 if (line >= window.buffer.lines.len) break;
-
-                CellRow row         = {};
-                row.line            = line;
-                row.cells.allocator = FrameArena;
-
                 Range line_range = window.buffer.lines[line];
 
                 Vec2 text_position_in_world_window_units = {0, line_offset * (float)line};
                 Vec2 text_position_in_window_units       = WindowWorldToWindowUnits(text_position_in_world_window_units, window);
                 Vec2 text_position_in_world_units        = WindowToWorldUnits(text_position_in_window_units, window);
                 Vec2 text_position_in_render_units       = WorldToRenderUnits(text_position_in_world_units, camera_offset_world_to_render_units);
+
+                CellRow row         = {};
+                row.line            = line;
+                row.cells.allocator = FrameArena;
                 row.rect.min        = text_position_in_render_units;
 
+                // Iterate the string and compute cells for current font
+                // we are also incorporating - new line and end of buffer glyphs
+                // into the stream!
                 String text = GetString(window.buffer, line_range);
                 if (font.texture.id == 0) font = GetFontDefault();
                 float textOffsetX = 0.0f;
                 float scaleFactor = font_size / font.baseSize; // Character quad scaling factor
-                for (int64_t i = 0; i < text.len;) {
+                for (int64_t i = 0;;) {
-                    int        codepointByteCount = 0;
+                    bool end_of_buffer    = i == window.buffer.len;
-                    int        codepoint          = GetCodepointNext(&text.data[i], &codepointByteCount);
+                    bool new_line         = i == line_range.max && i != window.buffer.len;
+                    bool in_range         = i < text.len;
+                    bool continue_looping = end_of_buffer || new_line || in_range;
+                    if (!continue_looping) break;
+
+                    int codepointByteCount = 1;
+                    int codepoint          = '\n';
+                    if (in_range) codepoint = GetCodepointNext(&text.data[i], &codepointByteCount);
+
                     int        index          = GetGlyphIndex(font, codepoint);
                     GlyphInfo *glyph          = font.glyphs + index;
                     Vec2       glyph_position = {text_position_in_render_units.x + textOffsetX, text_position_in_render_units.y};
@@ -204,6 +236,8 @@ int main() {
                     Vec2      cell_size      = {x_to_offset_by, font_size};
                     Rect2     cell_rect      = {glyph_position, Vector2Add(glyph_position, cell_size)};
                     Rectangle cell_rectangle = ToRectangle(cell_rect);
+
+                    // Clip everything that is outside the window and screen
                     if (CheckCollisionRecs(cell_rectangle, ToRectangle(window_rect_in_render_units_clamped_to_screen))) {
                         row.cells.add({cell_rect, codepoint, line_range.min + i});
                         row.rect.max = cell_rect.max;
@@ -231,16 +265,21 @@ int main() {
             BeginScissorMode((int)window_rect_in_render_units.min.x, (int)window_rect_in_render_units.min.y, (int)window_rect_in_render_units_size.x, (int)window_rect_in_render_units_size.y);
             ForItem(row, rows) {
                 For(row.cells) {
-                    if ((it.codepoint != ' ') && (it.codepoint != '\t')) {
+                    if (it.codepoint == '\n') {
+                        Vec2 mid = GetMid(it.rect);
+                        DrawCircle((int)mid.x, (int)mid.y, font_size / 8, {0, 0, 0, 120});
+                    } else if ((it.codepoint != ' ') && (it.codepoint != '\t')) {
                         DrawTextCodepoint(font, it.codepoint, it.rect.min, font_size, BLACK);
                     }
                 }
             }
 
+            // Draw the cursor
             ForItem(cursor, window.cursors) {
                 ForItem(row, rows) {
                     Range line_range = window.buffer.lines[row.line];
                     if (cursor.min >= line_range.min && cursor.min <= line_range.max) {
+
                         ForItem(cell, row.cells) {
                             if (cursor.min == cell.pos) {
                                 Rect2 rect = cell.rect;

src/text_editor/rect2.cpp

@@ -22,6 +22,14 @@ Rect2 Shrink(Rect2 result, float v) {
     return result;
 }
 
+Vec2 GetMid(Rect2 r) {
+    Vec2 size = GetSize(r);
+    size.x /= 2.f;
+    size.y /= 2.f;
+    Vec2 result = Vector2Add(r.min, size);
+    return result;
+}
+
 Rect2 CutLeft(Rect2 *r, float value) {
     float minx   = r->min.x;
     r->min.x     = Min(r->min.x + value, r->max.x);